KR20060135885A - Flame-retardant filler for plastics - Google Patents

Abstract

The invention relates to a flame-retardant filler based on aluminium hydroxide, its use in polymers and a method for its production, in which aluminium hydroxide in the form of a bayerite/gibbsite mixture is modified under pressure of temperatures of at least 170°C in the presence of water and crystal growth regulator, the aluminium hydroxide used as starting material having an average particle size d50 from 0.1 to 4mum.

Description

Flame retardant filler for plastics {FLAME-RETARDANT FILLER FOR PLASTICS}

The present invention relates to flame retardant fillers, methods for their preparation and their use in plastics and rubber.

The use of inorganic fillers for providing the flame retardancy of plastics and rubber, generally referred to as polymer systems, has long been known. In this context, metal hydroxides, in particular aluminum hydroxide (such as for example ATH) and magnesium hydroxide, have been used as inorganic fillers. Metal hydroxides are used alone or in combination with one another and sometimes in combination with other flame retardant additives including organic, for example halogen-containing additives.

Flame retardant action is essentially combustion based on the endothermic decomposition of crystals, the release of water into the form of water vapor, the dilution effect of the polymer matrix and the formation of some solid ash layer (“carbonization”). The mechanical stabilization of the polymer is brought to a certain degree. This may for example reduce the production of burning drips or may completely block it. In addition, the ash layer covering the surface of the combustion polymer acts as a kind of "protective layer" for the polymer layer beneath it, which can prevent rapid expansion of combustion.

Moreover, the use of combinations of such metal hydroxides and clay minerals, in particular organically inserted sheet silicates, for this purpose is described, for example, in EP 0 333 514 A1, WO-A-00 / 68312 and WO-A-. Known from 00/66657.

However, one disadvantage of known flame retardant fillers is that the minerals they contain are already decomposed at temperatures which occur during the manufacture or processing of the polymer system to be treated with them. For example, ATH already begins to decompose from about 200 ° C. This precludes their use in polymer systems that need to be processed at much higher temperatures, such as polyamide (PA) or polybutylene terephthalate (PBT). Standard ATH can only be used under certain conditions (eg 288 ° C. in so-called FR-4 circuit boards) in printed-circuit boards that require high temperature soldering.

Another possible disadvantage is the incompatibility between mineral and plastic. For example, there are incompatibilities in the case of magnesium hydroxide and polyester. This may be manifested as an excessive torque increase as an indication (increase in viscosity) of the chemical reaction in a Haake laboratory kneader, for example when using magnesium hydroxide at approximately 30-50% by weight in PBT.

Furthermore, flame retardant systems containing a combination of metal hydroxides or halogenated flame retardants and organically intercalated clay minerals (sheet silicates) (so-called "nanoclays"), for example bentonite or hectorite, are excessively heated upon heating. Discoloration has undesirable properties. This may be attributed to clay materials, which are essentially natural materials containing impurities of varying content and type. A further reason why discoloration occurs when using nanoclays is the limited thermal stability of chemical compounds used in the modification of natural or synthetic sheet silicates such as (but not exclusively) quaternary ammonium salts. Examples of these are distearyldimethyl ammonium chloride or stearylbenzyldimethyl ammonium chloride.

A further disadvantage in using the above-mentioned sheet silicates is that their flame retardant action becomes effective only through the interlayer separation (also called peeling) of the individual silicate layers. Usually this occurs during polymer synthesis or in existing mixing apparatuses such as internal mixers or Buss Ko-kneaders or twin-screw extruders or during mixing in roll mills. Thus, different mixing schemes or machines may produce different results, which is sometimes not reproducible. Moreover, the cost of the material is much higher than in metal hydroxides such as ATH.

The present invention is therefore inexpensive, synthetically prepared, and decomposed only at a higher temperature than with aluminum hydroxide, and elevated above a combination of metal hydroxide or halogenated flame retardant and organically intercalated sheet silicates. It is an object of the present invention to provide a flame retardant filler which exhibits less discoloration in and exhibits more preferable ashless formation than a known material, thereby further improving all the flame retardancy.

This object is achieved by hydrothermal treatment of aluminum hydroxide in the form of a bayerite / gibbsite mixture under pressure and at a temperature of at least 170 ° C. in the presence of water and acid or base as crystal growth regulator. This is solved by a flame retardant filler that can be prepared, wherein the average particle size d ₅₀ of aluminum hydroxide used as starting material is from 0.1 to 4 μm.

The bayerite portion of the mixture is for example at least 50% by weight. It is preferably at least 70%, in particular at least 80%, more preferably at least 90%.

The present invention includes such flame retardant fillers, methods for preparing the fillers, their use and polymer systems treated thereby. A preferred embodiment of the method is the subject of each dependent claim.

Surprisingly, it has been shown that the fillers according to the invention can be produced inexpensively using a simple method while exhibiting very good flame retardant properties. In particular, each is unexpected at all, with exceptional temperature stability, low discoloration tendency, and very good ash layer formation or no ash layer formed is consistent. In particular, because the filler variants produced are boehmite crystals (AlOOH), these very good flame retardant properties are surprising and unexpected. Unlike aluminum hydroxide (Al (OH) ₃ ), there is usually considerable damage in flame retardant action because the energy required for endothermic decomposition is much less in boehmite than in Al (OH) ₃ .

Starting materials for the production of flame retardant fillers according to the invention are aqueous suspensions of aluminum hydroxide (suspensions of the Bayerite / Gibsite mixture). The Bayerite portion in such a Bayerite / Gibsite mixture is, for example, at least 50%, in particular at least 70%, more preferably at least 80% and especially at least 90%, based on the weight of the Bayerite and Gibbsite.

The bayerite used as starting material can be produced, for example, according to the method described in EP 1 206 412 B1 (see in particular the description in paragraph 3 on page 3 of the document). If necessary, the gibbsite is added in a desired amount, and the BET surface area and particle size can be pre-adjusted by appropriately selecting the crystal precipitation conditions of the gibbsite and grinding it to the desired range if necessary.

The flame retardant filler according to the invention can be produced by hydrothermal treatment of the aluminum hydroxide used, which is under pressure up to 170 ° C. up to 340 ° C., in particular from 190 ° C. up to 250 ° C. or from 190 ° C. to 215 ° C. Requires the presence of water in. At the same time, crystal growth regulators must be present to obtain the filler according to the invention.

The aluminum hydroxide used preferably has a specific surface area of 1 to 100 m 2 / g, in particular 10 to 60 m 2 / g, with 20 to 40 m 2 / g being preferred and about 30 m 2 / g being particularly preferred.

In addition, the aluminum hydroxide used has an average particle size d ₅₀ of 0.1 to 4 μm, preferably 0.5 to 4 μm, in particular 1 to 3 μm, preferably about 2 μm.

Preferably, the aluminum hydroxide mixture (bayerite / gibbsite mixture) used has a BET specific surface area of approximately 30 m 2 / g, with a d ₅₀ value of preferably 0.1 to 4 μm, in particular 0.5 to 4 μm, Preferably it is 0.9-2.5 micrometers, Especially preferably, it is about 2 micrometers.

The amount of aluminum hydroxide used is always 1 to 30% by weight, preferably 5 to 20% by weight, in particular 6 to 10, such as 8% by weight, relative to the total weight of water and aluminum hydroxide. . Thus, in essence, an aqueous suspension of aluminum hydroxide is used, which has each stated content of solid aluminum hydroxide (bayerite / gibbsite mixture).

The hydrothermal treatment is carried out under pressure as providing modification, which pressure is for example in the range from 7 to 144.2 bar, in particular from 12 to 54.3 bar, preferably up to 23 bar. Such pressure may for example be self-forming in the autoclave.

The time required for hydrothermal treatment for the production of flame retardant fillers according to the invention also depends on the specific materials used, the amount used and the temperature and pressure conditions. The hydrothermal treatment can be carried out, for example, for a period of at least 10 minutes, in particular at least 15 minutes, preferably at least 30 minutes, more preferably at least about 1 hour, and preferably at most 2 days, especially at most 24 hours, more preferably. 5 hours or less is possible.

The crystal growth regulator used may be an acid, for example, and its pH value is preferably 0.5 to 6, in particular 1 to 5, preferably 1 to 4.5. Especially preferably, it is less than four.

However, bases can also be used as crystal growth regulators, wherein the pH value is preferably in the range from 10 to 14, in particular from 11 to 14, preferably from 12 to 14. Especially preferably, it is greater than 12.

For example, hydrochloric acid (HCl) or amidosulfonic acid (sulfamic acid NH ₂ SO ₃ H) can be used as crystal-growth-modifying acid. The acid actually used affects the macroscopic crystal structure. For example, the addition of hydrochloric acid produces a fibrous crystalline structure, while the use of amidosulfonic acid results in a layered (or plate) crystalline form. The acid content depends on the pH required.

Alternatively, sodium hydroxide solution (NaOH) can be used, for example, as a crystal-growing-modulating base. At this time, the amount of base also depends on the required pH. When sodium hydroxide solution (pH> 12) is added, an oval / elliptic crystal structure is produced.

The resulting modified solid is cooled to below 50-60 ° C., for example by filtration to separate it from the aqueous liquid, then washed with water and dried for example.

It may be dried in a conventional manner. For example, if desired, in a stove at 105 ° C. or higher, with mechanical grinding in a suitable grinder, for example, a pin mill grinder, a ball mill or an impact mill. Drying is suitable.

A preferred drying method is, for example, spray drying in a spray tower sold by Niro. Advantageously, air is used as the dry gas, adjusting the content and temperature so that the outlet temperature is between 100 and 150 ° C. Spray drying is preferably carried out in suspension. Preferably the solid washed with water is resuspended in water. The solids content in the suspension is 5 to 15% by weight, but can be raised to approximately 50% by weight with the addition of a suitable dispersant. Suitable dispersants are, for example, salts of polyacrylic acid, formic acid or acetic acid. These may be used in amounts conventionally used for this purpose, for example 0.01 to 5% by weight, preferably 0.05 to 1% by weight. Alternatively, paste sprays may also be used with spray towers of suitable design.

The flame retardant fillers according to the invention can be used for the flame retardant treatment of thermoplastics, elastomers and thermoset (uncured, or cured if necessary) polymers. In particular, the polymer may be a thermoplastic polymer (eg polyolefin, vinyl polymer, styrene polymer, polyacrylate), a thermoplastic polycondensate (eg polyamide, polyester) or a thermoset polycondensate (eg phenolic Plastics, unsaturated polyester resins) or polyadditions (eg, epoxy resins, polyurethanes). Both homopolymers and copolymers, and suitable mixtures of two or more of the above polymers can be considered. Preferred are (thermoplastic or crosslinked) polyolefins and copolymers thereof, such as PE, LDPE, LLDPE, HDPE, EVA, EEA, EMA, EBA, PP, as well as rubber and PVC.

The flame retardant fillers according to the invention may be used alone or in other known flame retardant fillers, in particular aluminum hydroxide (ATH), magnesium hydroxide (MDH), halogen-containing flame retardants, phosphorus or organophosphorus compounds or nitrogen-containing flame retardants (e.g. , Melanin cyanurate).

Correspondingly treated polymer systems contain a filler according to the invention in an amount sufficient for flame retardant purposes. Suitable contents are, for example, 0.1 to 250 parts (phr), in particular 5 to 150 parts (phr), preferably 10 to 120 parts (phr), according to the invention, relative to 100 parts (phr) of plastic, particularly preferably Is 15 to 80 parts (phr). If other flame retardant fillers are also used, their content is generally in the range of 249.9 to 0 parts (phr) for 100 parts of plastic. The abbreviation “phr” means “parts per 100 parts of polymer”.

Flame retardant fillers according to the invention can be prepared from aqueous bayerite-gibbsite suspensions, for example by hydrothermal treatment in an autoclave with the addition of one or more crystal growth regulators. Suitable autoclaves have a heating device to achieve the required final temperature, are sufficiently acid and pressure resistant, and are equipped with a stirrer. The crystal growth regulator used is for example one or more acids or one or more bases. At the end of the hydrothermal treatment, the solid obtained is filtered through a suitable filter, for example a paper filter, resuspended twice in hot distilled water at approximately 80 ° C. and filtered again. At least 1.5 l of water per 100 g of solid is used in the washing process.

This is followed by drying at 105 ° C. or higher, for example in a stove. After the stove is dried, it is comminutioned using, for example, a mortar. As an alternative, a mill such as a pin mill may be used. Drying in the spray tower may also be used as an alternative to stove drying. To this end, after the final washing operation, the filler according to the invention is resuspended. Preferably, this is done using distilled water and a solids content of approximately 10% by weight. In order to increase the solids content, suitable dispersants may be used, for example salts of polyacrylic acid.

However, it is also possible to carry out drying by means of a belt dryer or by means of fluidizing the product with hot air and passing it through a kind of mill.

The production of boehmite using aluminum hydroxide as raw material under hydrothermal conditions is already known.

The preparation of boehmite is described in WO 98/58876, but it is derived from the precipitation of supersaturated sodium aluminate solutions at temperatures below 100 ° C.

US-A-6 143 816 describes a process for producing hydrothermal water of boehmite, wherein the starting material is hydrargillite and not bayerite (preferably activated by grinding). Also, no crystal growth regulators are used. These crystals do not show good flame retardancy in the plastics according to the invention, as evidenced by the comparative examples of application V5 in Tables 1 and 2.

US-A-5 401 703 and US-A-5 306 680 describe hydrothermal methods for treating aluminum hydroxide under pressure in aqueous or alkaline solutions. "Aluminum hydroxide" is described only as starting material. In filler example 2 according to the invention, the bayerite / gibsite mixture is also hydrothermally treated in an alkaline solution. However, the crystallites shown in FIG. 3 are circular or oval and do not have the angled crystal structure shown in US-A-5 401 703 and US-A-5 306 680, FIGS. 4 and 5. However, this angled crystal structure is prepared as described in US-A-5 306 680 when the filler is prepared as described in Comparative Filler Example 1.

US-A-6 080 380 describes a hydrothermal method for converting aluminum hydroxide as a raw material to aluminum oxide at temperatures above 300 ° C. and corresponding high pressures.

The comparative filler Example 1 below shows the result of the boehmite preparation corresponding to the state of the art, rather than the result of the boehmite preparation according to the present invention.

filler Comparative example  One

To this end, 5 L of Gibbsite aqueous suspension with a solids content of 80 g / L was placed in a 10 L autoclave. Gibbsite (= hydrazilite) had an average grain diameter of 1.3 μm. With continued stirring, the suspension was heated to 230 ° C. and maintained spontaneously at this temperature for 14 minutes. The suspension was then cooled to room temperature, filtered, washed with distilled water, dried at 105 ° C. for 24 hours and then crushed using a mortar and pestle. 1 shows a scanning electron micrograph of Comparative Filler Example 1 (but not according to the invention). Each crystal does not have an ovoid / elliptic structure, nor is it a fibrous or layered structure. The Bayerite / Gibsite aqueous suspension used in the following filler examples according to the invention had a solids content of 80 g / l. The BET specific surface was 30 m ² / g and the average particle size (d ₅₀ ) was 2 μm.

filler Example  1 (invention)

In this filler example 1, 5 L of Bayerite / Gibsite suspension was placed in a 10 L autoclave. Amidosulfonic acid was then added as a crystal growth regulator until the pH value was set to 1.7. The suspension was then heated to 210 ° C. in an autoclave with constant stirring (heating rate: approximately 2 ° C./min) and held at this temperature for 1 hour with continued stirring. The pressure in the autoclave adjusts itself according to the dominant temperature. It was then cooled to 50-60 ° C. with stirring (cooling rate: approximately 1.5 ° C./min). The suspension was then filtered using filter paper. The filter cake thus obtained was then resuspended twice in distilled water and refiltered. In each suspension 1.5 L of distilled water per 100 g of solid was used.

The filtrate was then resuspended again in distilled water to a solids content of 10% by weight and then sprayed using a pilot-scale spray dryer (Niro Atomizer, "Minor Production" type). The throughput of the spray tower was approximately 2.5 kg / h solids, the inlet air temperature was approximately 500 ° C, and the outlet air temperature was 120-130 ° C. 2 shows a scanning electron micrograph of filler Example 1 according to the present invention.

The filler according to the invention prepared in this manner can then be used as flame retardant in the polymer mixture. It can be used, for example, in combination with conventional ATH, MDH, halogen-containing, phosphorus-containing or nitrogen-containing flame retardants or other flame retardant additives.

The fillers obtained can be characterized as follows:

Crystalline Boehmite, Lamellar

BET: 70 to 150 m ² / g

d ₁₀ : 0.2 to 0.5 탆

d ₅₀ : 0.5 to 3.0 탆

d ₉₀ : 3.0 to 7.0 탆

Individual, layered crystals of irregular appearance, which are sometimes coalesced as in FIG. 2 to have an irregular particle structure. Individual crystals (which do not mean particles consisting of crystals) have a thickness of about 0.03 to 0.08 μ, and fit into circles up to about 0.35 μm in diameter.

filler Example  2

In this filler example 2, 5 L of a bayerite-hydrazilite suspension was placed in a 10-liter autoclave. Then, concentrated sodium hydroxide solution was added as a crystal growth regulator until pH 13 was reached. The suspension was then heated in the autoclave to 180 ° C. (heating rate about 2 ° C./min) with constant stirring for 3 hours with continued stirring at this temperature. Maintained. The pressure in the autoclave adjusts itself according to the dominant temperature. It was then cooled while stirring while stirring to 50-60 ° C. (cooling rate: about 1.5 ° C./min). The suspension was then filtered through filter paper. The filter cake thus obtained was resuspended twice in distilled water and filtered again. 3 L of distilled water per 100 g of solid was used for each re-suspension.

The filtrate was then dried at 105 ° C. for 16 h on the stove and gently milled to remove lumps. 3 shows a scanning electron microscope (SEM) photograph of filler Example 2 according to the present invention.

The filler according to the invention prepared in this way can then be used as flame retardant in the polymer mixture. It can also be used in combination with, for example, conventional ATH, MDH, halogen-containing, phosphorus-containing or nitrogen-containing flame retardants or other flame retardant additives.

The fillers obtained can be characterized as follows:

Crystalline Boehmite, Oval to Elliptical

BET: 8 to 40 m ² / g

d ₁₀ : 0.4-0.7 μm

d ₅₀ : 0.7 to 2.2 탆

d ₉₀ : 2.2 to 4.5 탆

According to FIG. 3, if any, only a small amount (ie almost no particles are formed) is agglomerated ovoid / oval crystals. The individual crystals have a thickness of about 0.1 to 0.2 μm, a major axis length of about 1.6 to 3.2 μm and a minor axis length of about 1.4 to 2.0 μm.

filler Example  3

In this filler example 3, 5 L of a Bayerite-Gibsite suspension was placed in a 10-liter autoclave. Thereafter, hydrochloric acid was added as a crystal growth regulator until pH 1.7. The suspension was then heated in the autoclave to 210 ° C. (heating rate about 2 ° C./min) with continued stirring for 3 hours with continued stirring at this temperature. Maintained. The pressure in the autoclave adjusts itself according to the dominant temperature. It was then cooled while stirring while stirring to 50-60 ° C. (cooling rate: about 1.5 ° C./min). The suspension was then filtered through filter paper. The filter cake thus obtained was resuspended twice in distilled water and filtered again. 1.5 L of distilled water per 100 g of solid was used for each re-suspension.

The filtrate was then dried at 105 ° C. for 16 h on the stove and gently triturated to remove lumps. 4 shows a scanning electron micrograph of filler example 3 according to the present invention.

The fillers obtained can be characterized as follows:

Crystalline Boehmite, Fibrous Form

BET: 80 to 150 m ² / g

d ₁₀ : 0.04 to 0.15 탆

d ₅₀ : 0.15 to 0.8 탆

d ₉₀ : 0.8 to 2.0 탆

It is a fibrous crystal structure with partial adhesion to spherical form (particle) as shown in FIG. The individual fibers are about 0.3 to 3 μm in length and about 0.05 to 0.15 μm in diameter.

The filler according to the invention prepared in this way can then be used as flame retardant in the polymer mixture. It may also be used in combination with, for example, conventional ATH, MDH, halogen-containing, phosphorus-containing or nitrogen-containing flame retardants or other flame retardant additives.

Applicable Example

Examples of application have been provided for comparative products (Comparative Applications V1 to V5) with plastics treated with filler according to the invention (fillers examples 1, 2 and 3), all of which have a composition (Table 1) and suitable experiments. Results are provided for (Table 2).

The mixtures were all prepared in a roll mill (W150M type from the company Collin) in the usual manner known to those skilled in the art.

After preparation of the mixture in a roll mill, plastic sheets were made using a two-plate press, and the samples required for subsequent experiments were taken therefrom.

The following experiment was performed with the appropriate experimental values / results:

Cone calorimeter data according to ASTM E 1354 at 35 kW / m ² on 3 mm thick sheets. Values shown are kW / m ² , peak heat release rate (abbreviation of Peak Heat Release Rate: PHRR; this is the maximum power per area, measured on the cone calorimeter during combustion of the sample). The lower the PHRR value, the better the flameproofing of the sample. In s, the time to ignition (Time to Ignition; abbreviation: TTI; this is also the point at which the sample begins to burn due to exposure to heat in the cone calorimeter) is also shown. The higher the TTI value, the better the flameproofing of the sample. Therefore, at the same time as the low PHRR value, the highest TTI value is advantageous. Often, for further characterization, the ratio of TTI value to PHRR value (flame performance index, referred to as FPI) is calculated. From the definition of each individual amount, the higher the FPI, the better the flame retardant action.

Oxygen index (LOI index) according to ASTM D 2863 of specimens 15 cm long, 2 mm thick and 50 mm wide. Higher LOI values indicate better flameproofing.

UL94 V value of a 3.2 mm thick specimen. Classification according to UL94-V standard is "failed", V 2 (good), V 1 (good) or V 0 (best group).

Additionally, ashless formation was quantified by weighing the experimental specimens to be tested on a cone calorimeter, before and after combustion. The ratio A of the post-combustion mass M _n to the pre-combustion mass M _v can then be calculated:

A = M _m / M _v

This can be compared with the theoretically calculated ashless residue value A _th . Theoretical ashless residue A _th is calculated as an approximation, assuming that all organic components are burned without residues, and therefore ashless consists only of each inorganic component (ie the oxide of the filler is used). Thus, as is well known, aluminum hydroxide (ATH) Al (OH) ₃ and boehmite AlO (OH) are converted to Al ₂ O ₃ , and magnesium hydroxide (MDH) Mg (OH) ₂ is Converted to MgO.

Purely mathematically, this can be calculated based on molecular weight, for example, 100 g ATH is weighed only 65.3 g (or 65.3% in percentage) after full conversion to the oxide phase Al ₂ O ₃ due to loss of water. have. Similarly for MDH, 100 g Mg (OH) ₂ is converted to 69.1 g MgO (or 69.1% in percentage). Ignition in a crucible at 1200 ° C. resulted in a conversion factor percentage of 81.9% for the filler according to the invention. For example, the theoretical ashless residue A _th for a plastic composition consisting of:

Previous: phr weight% After combustion: phr weight% polymer 100 40 0 0 ATH 120 48 x 0.653 = 78.4 31.4 Filler of the invention 30 12 x 0.819 = 24.6 9.8 Sum 250 100 103 41.2

It can be calculated as follows:

A _th = 103/250 = 41.2%

The abbreviation “phr” means “parts per polymer bag”.

_Difference between measured value A and theoretical value A _th :

D = A- A _th

The larger the better ashless formation, the more the burned specimen has more ashless residue.

-Luminance level according to ISO Brightmess R457, on pressed plastic sheet from Elrepho to equipment type Elrepho 2000.

apply Example V1  ( Comparative example )

In a rolled sheet of 1000 g (= 251.95 phr) at a roll temperature of 140 ° C., 2.9 g (= 0.75 phr) of Albermarle Corporation antioxidant Ethanox 310 and 4.8 g (= 1.2 phr) of Degussa AG aminosilane Ameo with Together, 396.9 g (= 100 phr) of ExxonMobil ethylene vinyl acetate (EVA) Escorene on 595.4 g (= 150 phr) of Martinswerk GmbH's aluminum hydroxide Martinal OL-104 / LE with a Colin roll mill Ultra UL00119 was processed. Aminosilane ensures better coupling of the filler.

apply Example V2  ( Comparative example )

1000 g (= 251.95 phr) of rolled sheet and 2.9 g (= 0.75 phr) of the antioxidants Ethanox 310 from Albemarle Corporation and 4.8 g (= 1.2 phr) of aminosilane Ameo from Degussa AG with 31.8 at a roll temperature of 140 ° C. 396.9 g (= 100 phr) on a choline roll mill with 563.6 g (= 142 phr) of aluminum hydroxide Martinal OL-104 / LE from Martinswerk GmbH with g (= 8 phr) of Nanoclay 15 of Sued-Chemie Ethylene vinyl acetate (EVA) Escorene Ultra UL00119 from ExxonMobil was manufactured. Aminosilane ensures better coupling of the filler.

apply Example V3  ( Comparative example )

1000 g (= 251.95 phr) of rolled sheet at 5 ° C with 2.9 g (= 0.75 phr) of Albemarle Corporation's antioxidants Ethanox 310 and 4.8 g (= 1.2 phr) of aminosilane Ameo and 51.6 396.9 g (= 100 phr) on a choline roll mill with 543.8 g (= 137 phr) of aluminum hydroxide Martinal OL-104 / LE from Martinswerk GmbH with g (= 13 phr) of Nanoclay 15 of Sued-Chemie Ethylene vinyl acetate (EVA) Escorene Ultra UL00119 from ExxonMobil was manufactured. Aminosilane ensures better coupling of the filler.

apply Example V4  ( Comparative example )

In a 1000 g (= 251.95 phr) rolled sheet, 2.9 g (= 0.75 phr) of the antioxidants Ethanox 310 from Albemarle Corporation and 4.8 g (= 1.2 phr) of the aminosilane Ameo from Degussa AG and 178.6 at a roll temperature of 140 ° C. g (= 45 phr) Comparative Filler 396.9 g (416.9 g (= 105 phr) on a choline roll mill with aluminum hydroxide Martinal OL-104 / LE from Martinswerk GmbH with the filler according to the invention of Example 1 = 100 phr) of ethylene vinyl acetate (EVA) Escorene Ultra UL00119 from ExxonMobil. Aminosilane ensures better coupling of the filler.

apply Example V5  ( Comparative example )

In a 1000 g (= 251.95 phr) rolled sheet, 2.9 g (= 0.75 phr) of the antioxidants Ethanox 310 from Albemarle Corporation and 4.8 g (= 1.2 phr) of the aminosilane Ameo from Degussa AG and 178.6 at a roll temperature of 140 ° C. 396.9 g on a choline roll mill with 416.8 g (= 105 phr) of Martinswerk GmbH aluminum hydroxide Martinal OL-104 / LE from Martinswerk GmbH with a boehmite filler Apyral AOH 180 available from Nabaltec of g (= 45 phr) = 100 phr) of ethylene vinyl acetate (EVA) Escorene Ultra UL00119 from ExxonMobil. Aminosilane ensures better coupling of the filler.

apply Example  1 (invention)

1000 g (= 251.95 phr) rolled sheet with 2.9 g (= 0.75 phr) of antioxidants Ethanox 310 from Albemarle Corporation and 4.8 g (= 1.2 phr) of aminosilane Ameo from 11gus and 119.1 at a roll temperature of 140 ° C. g (= 30 phr) of 396.9 g (= 476.8 g (= 120 phr) on a choline roll mill with aluminum hydroxide Martinal OL-104 / LE from Martinswerk GmbH with filler according to the invention (filler example 1) 100 phr) of ethylene vinyl acetate (EVA) Escorene Ultra UL00119 from ExxonMobil was processed. Aminosilane ensures better coupling of the filler.

apply Example  2 (invention)

In a 1000 g (= 251.95 phr) rolled sheet, 2.9 g (= 0.75 phr) of the antioxidants Ethanox 310 from Albemarle Corporation and 4.8 g (= 1.2 phr) of the aminosilane Ameo from Degussa AG and 178.6 at a roll temperature of 140 ° C. g (= 45 phr) of 396.9 g (=) on a choline roll mill with 416.8 g (= 105 phr) of aluminum hydroxide Martinal OL-104 / LE from Martinswerk GmbH with filler according to the invention (filler example 1) 100 phr) of ethylene vinyl acetate (EVA) Escorene Ultra UL00119 from ExxonMobil was processed. Aminosilane ensures better coupling of the filler.

apply Example  3 (invention)

In a 1000 g (= 251.95 phr) rolled sheet, 2.9 g (= 0.75 phr) of the antioxidants Ethanox 310 from Albemarle Corporation and 4.8 g (= 1.2 phr) of the aminosilane Ameo from Degussa AG and 178.6 at a roll temperature of 140 ° C. 396.9 g (= 45 phr) on a choline roll mill with 416.8 g (= 105 phr) of the aluminum hydroxide Martinal OL-104 / LE from Martinswerk GmbH with a filler according to the invention (filler example 2) 100 phr) of ethylene vinyl acetate (EVA) Escorene Ultra UL00119 from ExxonMobil was processed. Aminosilane ensures better coupling of the filler.

apply Example  4 (invention)

396.9 g (= 100 phr) of ethylene vinyl acetate (EVA) (Escorene Ultra UL00119 from ExxonMobil) were added to 535.8 g (= 135 phr) of aluminum hydroxide (Martinswerk GmbH, Martinal OL-104) in a Collin roll mill. / LE) and 59.5 g (= 15 phr) of the filler according to the invention (filler example 3) and 4.8 g (= 1.2 phr) of aminosilane (Ameo from Degussa AG) and 2.9 g (= 0.75 phr) of antioxidant (Ethanox 310 from Albemarle Corporation) was processed at a roll temperature of 140 ° C. for a roll sheet of 1000 g (= 251.95 phr). Aminosilane ensures better coupling of the filler to the polymer matrix.

Table 1 below shows the formulations of the examples according to the invention and comparative examples of the application.

Formulation Comparative example Example Example Example Example V1 V2 V3 V4 V5 One 2 3 4 phr phr phr phr phr phr phr phr phr EVA, 19% VA 100 100 100 100 100 100 100 100 100 ATH OL 104 / LE 150 142 137 105 105 120 105 105 135 The present invention (filler example 1) - - - - - 30 45 - - The present invention (filler example 2) - - - - - - - 45 - The present invention (filler example 3) - - - - - - - - 15 Nanoclay, Nanofil 15 - 8 13 - - - - - - Filler, Comparative Example 1 - - - 45 - - - - - Apyral AOH 180 - - - - 45 - - - - Aminosilane 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 Ethanox 310 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75

Table 2 sets forth the values for TTI, PHRR, FPI, LOI, UL94V, D and certain luminance and yellowness values measured for an application according to the invention and a comparative example of the application.

Comparative example Example Example Example Example V1 V2 V3 V4 V5 One 2 3 4 TTI (s) 121 150 188 105 114 129 145 122 - PHRR (kW / ㎡) 119 106 144 164 156 83 89 103 - FPI = TTI / PHRR (㎡s / kW) 1.02 1.42 1.31 0.64 0.73 1.55 1.63 1.18 - LOI, 2x 50 mm ₂ , (% O ₂ ) 37.8 36.8 36.3 33 38 39.2 38.2 38.3 42.8 UL94V, 3.2 mm failure V O V O failure failure V O V O V O V O D (%) 3.6 5.4 4.6 5.6 - 7.4 9.7 8.1 - Brightness (%) 60.5 - 27.3 - - - 47.2 - - Yellowness (%) 30.1 - 46.3 - - - 26.3 - -

Mixtures V1 in which the EVA mixtures of the examples of applications 1, 2 and 3 incorporating the fillers according to the invention are always replaced with each filler according to the invention, with some ATH replaced by the same total filling of the mixture). Compared with, it was found that it started riding later (higher TTI value) and at the same time had a substantially lower PHRR value. The latter means that the specimen produces a lower heat radiation maximum during combustion, ie it burns but with less intensity. The EVA mixture treated according to the invention also shows the highest FPI (Fire Performance Index) value compared to the comparative example of application V1. Obviously, the TTI and FPI values are also increased using nanoclays in the comparative examples of applications V2 and V3 compared to the mixture V1 which only flames with ATH; It can be seen that in the comparative example of application V3, the capacity of the nanoclay is higher than V2, the PHRR value rises again above the PHRR value of the comparative example of application V1, indicating more intensive combustion.

In particular, the comparison of V4 and V5 with V1 shows that when fillers according to the invention are used (ie boehmite prepared according to the prior art), no advantage in combustion values is obtained. Boehmite prepared according to Comparative Filler Example 1 was used at V4 and commercially available boehmite Apyral AOH 180 from Nabaltec was used at V5. The mixture begins to burn earlier (lower TTI value than V1) and shows the highest PHRR value in Table 2. Thus, the FPI indicator is also the lowest in Table 2. In addition, no advantage is obtained in comparison to V1 for LOI values and UL94V classification. In particular, V4 shows a marked decrease of only 33% O ₂ .

The oxygen index LOI is only improved in the inventive mixtures (filler examples 1, 2 and 3) compared to V1. V2 and V3 (both mixtures contain nanoclay) have even slightly lower (and therefore worse) LOI values than V1.

In contrast to the comparative example of application V1, all the fillers according to the invention (filler examples 1, 2 and 3) also induce combustion classification with UL class VO.

The difference D between the ashless residue value A determined from the measurement and the theoretically calculated value A _th is the highest value for the mixtures of the examples of applications 1, 2 and 3 and the fillers according to the invention (filler examples 1 and 2). (The manufacturing data indicate that 35% by weight is organic and no significant amount is present after the combustion process, so a 65% percentage conversion index was used for the mixture with nanoclays).

As an example, the brightness and yellowness were also measured on the sheets pressed in the examples of application 2 according to the invention and comparative examples of applications V1 and V3. Compared to the nanoclay mixtures, the advantages in the example of application 2 according to the invention are very clear: in this case, 45 phr of the filler according to the invention from filler example 1 is incorporated, but using 13 phr of nanoclay The brightness is brighter, the yellowness is lower than in V3, and includes a relatively low ATH substitution.

V6  apply Example  (Comparative)

100 phr (= 350 g) of polypropylene (PP) Moplen RP 320 H (manufactured by Basell) was charged in a Collin roll mill with 185.7 phr (= 650 g) magnesium hydroxide Magnifin H 5 MV (manufactured by Martinswerk GmbH) and a roll at 170 ° C. Processing at temperature produced 285.5 phr (= 1000 g) of rolled sheet.

V7  apply Example  (Comparative)

100 phr (= 350 g) of Polypropylene (PP) Moplen RP 320 H (manufactured by Basell) Collin roll mill 170.2 phr (= 595.7 g) of magnesium hydroxide Magnifin H 5 MV (manufactured by Martinswerk GmbH) and 15.5 phr (= 54.3 g) was processed with a nanoclay Nanofil 15 (manufactured by Sud-Chemie) at a roll temperature of 170 ° C to prepare a rolled sheet 285.7 phr (= 1000 g).

apply Example  5 (invention)

10 phr (= 350 g) of polypropylene (PP) Moplen RP 320 H (manufactured by Borealis) was added to 130 phr (= 455 g) magnesium hydroxide Magnifin H 5 MV (manufactured by Martinswerk GmbH) and 55.7 phr (= 195 g) of a filler according to the invention (filler example 1) were processed at a roll temperature of 170 ° C. to produce 285.7 phr (= 1000 g) of rolled sheet.

Table 3 below shows the formulations of Examples 5 and Comparative Examples of Applications V6 and V7.

Formulation Comparative Example V6 Comparative Example V7 Example 5 Phr Phr Phr PP Moplen RP 320H 100 100 100 Magmifin H 5 MV 185.7 170.2 130 Filler according to the present invention (filler example 1) - - 55.7 Nanoclay, Nanofil 15 - 15.5 -

Table 4 shows the difference D values between the ash residue and the theoretical ashless residue measured for the comparative examples of applications V6 and V7 and the examples of application 5 according to the invention.

Comparative Example V6 Comparative Example V7 Example 5 D (%) 5.3 0.5 7.8

It was found that there is substantial improvement in the residual material having the filler according to the invention.

FIG. 5 shows the TGA of the filler according to the invention from filler example 1, compared to ATH Martinal OL-104 / LE (manufactured by Martinswerk GmbH) and MDH Magnifin H 5 (manufactured by Martinswerk GmbH). It was measured at a heating rate of 1 K / min in air.

It can be clearly seen from FIG. 5 that the filler according to the invention has improved thermal stability.

Claims (23)

Average particles of aluminum hydroxide, obtained as a starting material, obtained by modifying aluminum hydroxide in the form of a Bayerite / Gibsite mixture at a temperature of at least 170 ° C. in the presence of water and acid or base as a crystal growth regulator under reduced pressure. Flame retardant filler based on aluminum hydroxide, characterized in that the size d ₅₀ is 0.1 to 4 μm. The flame retardant filler according to claim 1, which is a crystalline boehmite having the following parameters: BET: 70 to 150 m 2 / g d ₁₀ : 0.2 to 0.5 탆 d ₅₀ : 0.5 to 3.0 탆 d ₉₀ : 3.0 to 7.0 mu m. The flame retardant filler according to claim 1, which is a crystalline boehmite having the following parameters: BET: 8 to 40 m 2 / g d ₁₀ : 0.4-0.7 μm d ₅₀ : 0.7 to 2.2 탆 d ₉₀ : 2.2 to 4.5 탆. The flame retardant filler according to claim 1, which is a crystalline boehmite having the following parameters: BET: 80 to 150 m 2 / g d ₁₀ : 0.04 to 0.15 탆 d ₅₀ : 0.15 to 0.8 탆 d ₉₀ : 0.8 to 2.0 μm. Aluminum hydroxide in the form of a Bayerite / Gibsite mixture is modified under pressure at a temperature of 170 ° C. or higher in the presence of water and acid or base as crystal growth regulator, and the average particle size of aluminum hydroxide used as starting material d ₅₀ is 0.1 to 4 μm, a method for producing a flame-retardant filler based on aluminum hydroxide. The method according to claim 5, wherein the bayerite portion in the bayerite / gibsite mixture is at least 50%, preferably at least 70%, more preferably at least 80%, in particular based on the weight of the bayerite and the gibbsite At least 90% present. 8. The specific surface area of the aluminum hydroxide according to claim 6 or 7, which is used as starting material, is from 1 to 100 m 2 / g, in particular from 10 to 60 m 2 / g, preferably from 20 to 40 m 2 / g, particularly preferred. Preferably about 30 m 2 / g. 8. The method according to claim 5, wherein the average particle size d ₅₀ of the aluminum hydroxide used as starting material is 0.5 to 4 μm, especially 1 to 3 μm, particularly preferably about 2 μm. How to feature. 9. The amount of aluminum hydroxide according to claim 5, wherein the amount of aluminum hydroxide is 1 to 30% by weight, preferably 5 to 20% by weight, in particular 6, based on the total weight of water and aluminum hydroxide. To 10% by weight. 10. The method according to any one of claims 5 to 9, wherein the temperature is in the range of 170 ° C to 340 ° C, preferably 190 ° C to 250 ° C, more preferably 190 ° C to 215 ° C. 10. The process according to claim 5, wherein the modification is carried out at a pressure in the range of 7 to 144.2 bar, in particular 12 to 54.3 bar, preferably 23 bar or less. 12. The method according to any one of claims 5 to 11, wherein the modification is carried out under self pressure in the autoclave. The process according to claim 5, wherein the modification is carried out for a period of at least 10 minutes, in particular at least 15 minutes, preferably at least 30 minutes, more preferably at least about 1 hour. 14. The acid according to claim 5, wherein an acid having a pH value preferably in the range of 0.5 to 6, especially 1 to 5, preferably 1 to 4.5, in particular less than 4 is used as crystal growth regulator, Or a base whose pH value preferably ranges from 10 to 14, in particular from 11 to 14, preferably from 12 to 14, in particular more than 12, is used as crystal growth regulator. The method according to claim 13, wherein hydrochloric acid or amidosulfonic acid is used as the crystal growth control acid or sodium hydroxide is used as the crystal growth control base. The process according to any one of claims 5 to 15, characterized in that the solid produced after cooling is separated from the aqueous liquid, washed and dried. 17. The process according to claim 16, wherein the drying is carried out in a stove, by spray drying, in a belt dryer or by conveying the product through a kind of mill by liquefying the product with hot air. 17. The process according to claim 16, wherein the washed solid is redispersed for spray drying by addition of a dispersant if necessary. 19. Obtained by the method of any one of claims 5 to 18, in particular for flame retardation of polymers or mixtures of polymers or mixtures thereof, which are thermoplastic, elastomeric and thermoset (all in uncrosslinked or crosslinked form), or Or the use of a flame-retardant filler based on aluminum hydroxide according to any one of claims 1 to 4. 20. The process according to claim 19, wherein the polymer is selected from thermoplastic polymers, in particular polyolefins, vinyl polymers, styrene polymers, polyacrylates; Thermoplastic polycondensates, in particular polyamines, polyesters; Thermosetting polycondensates, especially phenolic plastics, unsaturated polyester resins; Or polyadducts, in particular epoxy resins, polyurethanes, which are homopolymers or copolymers or two or more polymers, in particular thermoplastic or crosslinked polyolefins and copolymers thereof, preferably PE, LDPE, LLDPE, HDPE , EVA, EEA, EMA, EBA, PP, or a suitable mixture of rubber or PVC. The flame retardant filler according to claim 19 or 20, wherein the flame retardant filler is used alone or in flame retardant additives, in particular aluminum hydroxide (ATH), magnesium hydroxide (MDH), huntite, halogen-containing flame retardant, phosphorus and / or Use in combination with organophosphorus compounds or nitrogen-containing flame retardants, in particular melamine cyanurate. The polymer or polymer mixture can be obtained by the method of any one of claims 5 to 18 or flame retarded with a filler based on aluminum hydroxide according to any one of claims 1 to 4, if necessary. , Other flame retardant additives, in particular aluminum hydroxide (ATH), magnesium hydroxide (MDH), huntite, halogen-containing flame retardants, phosphorus and / or organophosphorus compounds, or nitrogen-containing flame retardants, in particular melamine cyanurate One or more polymer compositions may be added. The process according to claim 22, which is based on 100 parts (phr) of the polymer at 0.1 to 250 parts (phr), in particular 5 to 150 parts (phr), preferably 10 to 120 parts (phr), particularly preferably 15 to 80 parts (phr) of a filler according to the invention, and if other flame retardant additives are also used, the amount thereof is preferably in the range of 249.9 to 0 parts (phr) based on 100 parts (phr) of the polymer. Characterized by a polymer composition.

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